Influence of wet-dry history on the mixed fracture properties of dense asphalt mixture based on ASCB test

Abstract

The coupling effects of traffic loads and rainfall may cause premature cracking in asphalt layer. Consequently, it is of interest to study the influence of rainfall on the fracture resistance of asphalt mixtures. However, the on-site testing presents significant challenges. Thus, this study designs the wet-dry history to simulate the conditions experienced by asphalt mixture in the field, employing the asymmetric semi-circular bend (ASCB) test to determine the mixed fracture performance of asphalt mixture. The fracture criteria of the asphalt mixture before and after wet-dry cycling treatment were analyzed, and the propagation of crack mouth was measured using digital image correlation technology. Results indicate that wet-dry cycles lead to the mass loss in asphalt mixture, with higher loss correlating to more cycles. Wet-dry history causes an increase in the stress intensity factor at medium temperature. For the condition of 24 cycles, the low-temperature fracture toughness of mode I is significantly reduced, and the low-temperature fracture toughness increases under mixed and II modes, which results in an increased ratio of K_II/K_IC. The low-temperature fracture energy of asphalt mixture is susceptible to wet-dry history. Empirical fracture criteria such as linear model exhibit smaller deviation than the MTS and GMTS criteria. Wet-dry history notably reduces the low-temperature plastic deformation and diminishes the crack propagation deforming capability. The load-CMOD curve at low temperature is suggested to assess the impact of wet-dry history on the crack propagation capability of asphalt mixture.